Alkaline Detergent Soil Release Polymer Stability
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Solution Overview
Problem
Existing alkaline liquid detergent compositions face stability issues with soil release polymers (SRPs) due to hydrolytic breakdown, especially when triethanoloamine (TEA) is present, leading to compromised performance and solubility problems, particularly for SRPs designed for polyester fabrics.
Innovation Solution
Development of a stable alkaline isotropic detergent liquid composition incorporating a polyester substantive nonionic soil release polymer with specific molecular structure modifications, such as capped oligomers of polyethylene glycol and a midblock motif with hindered ester bonds, to maintain soil release performance and stability even in the presence of TEA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyester SRPs are used in alkaline liquid detergent compositions, then soil release performance on polyester fabrics is achieved, but the polymer undergoes hydrolytic breakdown during storage compromising stability and performance
Solution Approach 1:
The patent modifies the chemical structure parameters of the polyester SRP by incorporating sterically hindered ester bonds and specific monomer compositions (ethylene oxide units with adjacent substituents) to reduce hydrolytic susceptibility. The polymer is designed with controlled molecular weight (Mw 1000-10000) and specific end-group modifications to enhance stability in alkaline conditions while preserving soil release functionality.
Solution Approach 2:
The invention creates a composite polymer structure combining polyester segments with hydrophilic end blocks (ethylene oxide or propylene oxide units). This composite architecture provides both fabric substantivity (from polyester mid-block) and solubility/stability in alkaline liquid detergent compositions (from hydrophilic end blocks), while the specific composition ratio and structural features protect against hydrolysis.
2Stability of the object's composition
If triethanoloamine (TEA) is used as neutralising agent and buffer in the detergent composition, then pH control and buffering capacity are improved, but the decomposition of polyester SRPs is catalysed worsening polymer stability
Solution Approach 1:
The patent modifies the polymer structure to include sterically hindered ester bonds and specific monomer configurations that reduce the catalytic effect of TEA on hydrolysis. The use of substituted ethylene oxide units and controlled molecular weight parameters creates a polymer that is less susceptible to TEA-catalysed decomposition while maintaining the desired pH buffering capacity of the detergent composition.
3Reliability
If SRPs with permanent charge are used to improve soil release performance, then cleaning efficiency is enhanced, but compatibility with anionic surfactants is lost worsening formulation stability
Solution Approach 1:
The patent employs nonionic polyester SRPs with hydrophilic end blocks that provide solubility in aqueous alkaline environments without introducing permanent charges. This homogeneous nonionic structure ensures compatibility with anionic surfactants and other charged species in the detergent formulation, avoiding electrostatic interactions that would compromise formulation stability while maintaining effective soil release performance through hydrophobic-hydrophilic balance.
4Quantity of substance
If conventional polyester SRPs are used in concentrated alkaline liquid detergent compositions, then solubility is achieved, but the liquid turns hazy and product performance is compromised
Solution Approach 1:
The patent creates a composite polymer structure with polyester mid-blocks for fabric substantivity and hydrophilic end blocks (ethylene oxide or propylene oxide units) for solubility. This composite architecture allows the polymer to remain isotropically dissolved in concentrated alkaline liquid detergent compositions at effective concentrations without causing hazing, as the hydrophilic end blocks ensure adequate water solubility while the polyester segments provide the necessary fabric affinity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified SRPs ensure effective soil release on polyester fabrics with ΔE of 5 or less after storage, maintaining performance and stability at elevated temperatures and pH levels, thereby enhancing the durability and effectiveness of the detergent composition.
Implementation Method 1
the resistance of most prior art polyester SRPs to hydrolytic attack is insufficient to allow them to be incorporated into alkaline liquid detergent compositions with sufficient stability that their performance is not compromised due to hydrolytic breakdown on storage of the composition
Implementation Method 2
a SRP substantive to polyester... the normally hydrophobic polyester fabric surface once the fabric substantive mid block has caused the SRP to deposit on the surface
Data Source
AI summary
An aqueous alkaline isotropic concentrated detergent liquid composition with an undiluted pH of at least 7.8 and at most 9 comprising: a)10 to 60 wt% non-soap surfactant, b) 0 to 20 wt% hydrotrope, c) 0 to 4 wt% soap, d) 0 to 10 wt% nonionic EPEI, e) at least 1 wt% triethanolamine, characterised in that dissolved in the alkaline isotropic liquid there is: f) at least 1 wt%, preferably at least 1.5 wt% of a polyester substantive nonionic soil release polymer of the type E-M-L-E, where the midblock M is connected to a generally hydrophilic end block E and blocks E each comprise capped oligomers of polyethylene glycol remote from the midblock, with at least 10 EO repeat units, the end blocks being free from ester bonds, either directly or via linking moiety L which comprises the motif: B-Ar-B where B is selected from urethane, amide and ester moieties and Ar is,4 phenylene, and midblock M comprises the motif: wherein R1 and R2 may be the same or different selected from C1-C4 alkyl, C1-C4 alkoxy and Hydrogen, provided that R1 and R2 may not both be hydrogen, n is at least 2, preferably more than 5, the ester bonds may by 2 formed the other way around (not shown), if they are so reversed then all of them will be so reversed, G3107 (C) CPL -78- wherein the composition comprising the polymer provides soil release less than a ?E of 5 with DMO on woven polyester after storage of the polymer in the detergent composition at 60°C for 8 days at a pH >7.5.